KEEPING UP WITH KRIS: The Nets, as they remake their roster for the move to Brooklyn, are expected to re-sign forward Kris Humphries. Photo: Christopher Sadowski

WASHINGTON — After entering free agency with a roster full of uncertainty, the Nets have engineered a nearly complete overhaul of their team after the first two weeks of free agency.

But even after all of the millions of Russian billionaire Mikhail Prokhorov’s money that have been invested in the team this summer — from re-signing Deron Williams, Gerald Wallace and Brook Lopez to trading for six-time All-Star Joe Johnson — general manager Billy King still has more work to do in order to finish rounding out the Nets’ roster.

He filled one important hole on Saturday night, when the Nets signed C.J. Watson to back up Williams at the point. Another should be filled shortly if, as expected, the Nets eventually re-sign power forward Kris Humphries.

Once that situation is resolved, however, the Nets still will have two weaknesses on their roster that both King and Nets coach Avery Johnson have made mention of recently: backups at both small forward and center.

One possibility to back up Wallace at small forward is Damion James, whom the Nets drafted in 2010 and who spent much of last season sidelined following surgery to repair a stress fracture of the fifth metatarsal in his right foot. The injury was a recurrence of one James initially suffered during his rookie season.

A source said the Nets have spoken to James since free agency began about the possibility of bringing back the 6-foot-7, 225-pound forward, after declining the option on his contract during the year and making him a free agent.

James, who averaged 4.9 points and 4.7 rebounds in seven games — all starts — before sitting out the rest of the season following surgery to repair the stress fracture, has meetings scheduled with multiple teams this week.

As for the Nets’ backup center spot, an overseas report said the team was about to offer Bryant Dunston — who played at Fordham and played well in Orlando with the Nets’ Summer League team — a guaranteed contract for next season, but a source shot down the report.